Place corn in large paper sack.,Add nuts, if desired.,In a deep bowl combine butter, brown sugar, white Karo syrup and salt. Micro until it boils, then 2 more minutes.,Stir in soda.,Pour sauce over corn in bag and shake well.,Micro for 1 minute and 15 seconds.,Take out and shake well.,Micro again 1 minute and 25 seconds.,Tear bag open.,______